that, given three integers A, B and K, returns the number of integers within the range [A..B] that are divisible by K, i.e.:{ i : A ≤ i ≤ B, i mod K = 0 }For example, for A = 6, B = 11 and K = 2, your function should return 3, because there are three numbers divisible by 2 within the range [6..11], namely 6, 8 and 10.

A is an integer within the range [0..2,000,000,000];B is an integer within the range [0..2,000,000,000];K is an integer within the range [1..2,000,000,000];A ≤ B.